In recent years, automobiles using fuel cells as a source of drive energy have attracted attention as one possible measure for addressing environmental problems. In conjunction with this, there has been a noticeable effort to develop technology for installing fuel cells in the front section of automobiles. For example, Japanese Patent No. 3767423 describes a fuel cell-powered automobile in which a fuel cell is installed in the front end of the vehicle, the power generating cells of the fuel cell are stacked in the width direction of the vehicle, and a circuit breaker and an electric output terminal for receiving electric power from the fuel cell are arranged on a side face of the vehicle. In the described configuration, the fuel cell is housed in a casing for protection.
Because the position of the electric output terminal for receiving electric power from the fuel cell moves due to heat expansion of the fuel cell, there has also been proposed a fuel cell output terminal housed in a bellows as described in Japanese Patent Publication JP-A 5-74473, and an output cable for receiving electric power from the fuel cell covered with an insulator as described in Japanese Patent Publication JP-A 2002-208314.
Meanwhile, technology for producing high voltage fuel cells having a large capacity has progressed, and high-performance vehicles in which such cells are installed are now being studied. However, as the voltage and capacity of fuel cells increase, there dimensions such as width and length become large, possibly to the extent that it may not be possible to stack the power generating cells in the width direction, in which case the fuel cell cannot be installed in the width direction of the vehicle. In such a case, it might become necessary to stack the power generating cells in the longitudinal direction of the vehicle and to install the fuel cell in the longitudinal direction of the vehicle.
In a case where the fuel cell is installed in the longitudinal direction within the front section of the vehicle, a fuel pipe and the like connecting to the fuel cell are arranged on the rear side in a fuel cell installing space of the vehicle in view of safety. In such a configuration, the electric output terminal from the power generating cells would likely be arranged on the front end of the power generating cells, in the vehicle front section, the side opposite to the connection ports of the fuel pipe and the like.
When the electric output terminal is arranged towards the front of the vehicle, the casing in which the fuel cell is housed may be deformed if the vehicle body adjacent to the fuel cell is deformed as a result of the vehicle colliding with an object. Although an insulation coating is applied to the inner surface of the casing for the fuel cell, the insulation coating can become broken because of the contact between the deformed casing and the electric output terminal, in which case the electric output terminal and the casing may become electrically connected, possibly resulting in a short circuiting of the electrical system.
When the fuel cell is installed on the vehicle front side as described above, the power generating cells are stacked along the longitudinal direction of the vehicle, and a side face of the stacked-cell body becomes a side face of the vehicle. With such a configuration, the side face of the casing in which the fuel cell is housed might become deformed due to the deformation of the vehicle side face in the event of a collision impacting the side of the vehicle. When the side face of the casing is deformed, the deformed casing comes into contact with the side face of the stacked-cell body, resulting in a possibility that a short circuit occurs between the individual stacked power generating cells through the metallic casing. Even when the inner surface of the metallic casing is insulation-coated, contact of the metallic casing with the power generating cells may still damage the insulation coating, with the result, again, that a short circuit as described above may occur.
If a short circuit occurs between the electric output terminal of the fuel cell and the vehicle or between the power generating cells, there were problems that an abnormal electric potential is generated in the power generating cells, for example, sintering of a catalyst, oxidation of supported carbon, or the like is generated, resulting in deterioration of the catalyst.